The present invention relates to wound dressings and methods for making such wound dressings and, in particular, to a thin film wound dressing which can be applied to a patient without stretching, and a method for the continuous production of a large number of such wound dressings.
Wound dressings, consisting of a urethane film having adhesive on one side for carrying an absorbent pad and adhering to a patient""s skin surrounding an open wound, are known in the art. The flexible nature of the urethane film permits the dressing to conform to virtually any contour of the patient""s skin at the location where the dressing is applied. The flexibility and thinness of the urethane film, however, present the problem of applying the wound dressing to the patient without stretching the urethane film. Stretching of the dressing prior to or during application to a patient may momentarily expand the stretchable urethane film and, even though the dressing may appear smooth when applied to the patient, it will very quickly contract after the stretching forces are relieved, thereby causing discomfort to the patient and irritation to the area surrounding the wound. On weak or damaged skin, as in the elderly, the stretching forces may even cause abscesses or other skin damage.
One proposed solution to the stretching problem has been to use heavier or thicker urethane films. Unfortunately, heavier urethane films are undesirable as a wound dressing due to decreased flexibility and less gas permeability. Many conventional urethane films are about 1.0 mil or more thick. Although thinner urethane films will achieve greater gas permeability, moisture vapor transmission rates and increased flexibility and comfort, use of such thin films has been unsuccessful because they are relatively fragile and consequently difficult to work with during manufacture and assembly of the wound dressing.
Another proposed solution to this problem is to attach a flexible but non-stretching backing sheet to the urethane film using adhesive. The backing sheet remains in contact with the urethane film while the dressing is being applied to the patient, thereby eliminating stretching during application of the dressing. After the wound dressing has been attached to the patient, the backing sheet is subsequently peeled from the urethane film. Unfortunately, methods using adhesive to attach the urethane film to conventional backing sheets have been unable to handle the fragile and thin urethane films.
Another problem encountered when applying the polyurethane film to the wound is maintaining the sterility of the dressing during the application process. Previous products such as a polyurethane film wound dressings Ensure-IT (Deseret Medical, Inc.) and POLYSKIN(copyright) transparent dressing (Kendall Company, Boston, Mass.) required contact between fingers and the adhesive surface of the polyurethane film during application. It will be appreciated that such contact is undesirable as it may potentially contaminate the urethane film.
In view of the foregoing, it is an object of the present invention to provide a wound dressing which provides ease of application while maintaining sterility of the urethane film and the absorbent pad.
Another object of the invention is to provide a tab system that allows support of the non-stretchable wound dressing following removal of the carrier sheet. A related object is to provide a wound dressing having a tab system that allows manipulation of the wound dressing without contaminating contact between the sterile urethane film and the user""s fingers.
One object of the invention is to provide a wound dressing having a tab system that permits application of the wound dressing with one hand.
Yet another object of the invention is the coding of the tabs to indicate the sequential order of utilization of the tabs.
Still another object of the present invention is to provide a wound dressing having a unique thin urethane film which enhances healing and maximizes gas permeability with the patient""s skin. A more specific object is to provide a thin urethane film having a thickness of about 1.0 mil or less.
It is an object of the present invention to provide a thin film, non-stretchable wound dressing which can be manufactured by overlying a series of continuous strips.
In accordance with these objects, the present invention provides a non-stretchable wound dressing consisting of a thin film of material such as polyurethane which is less than about 1.0 mil thick, more preferably about 0.75 mils thick, and most preferably less than about 0.75 mil thick. The wound dressing has a non-stretchable cover sheet, such as MYLAR(copyright), onto which the urethane film is cast.
The urethane film has an adhesive side and first and second releasable ends. The adhesive side of the first releasable end receives a first gripping tab, which extends outboard of the left releasable end of the cover sheet. The cover sheet and first gripping tab are in adjacent contact with each other but are not adhesively attached so that they may be freely separated from each other. A second gripping tab may be attached to the other side of the urethane film. The adhesive side of the second releasable end receives an intermediate liner. An absorbent pad is centrally positioned on the urethane film. Finally, a carrier sheet is attached to the urethane film surrounding the pad, thereby covering and protecting the sterility of the pad.
In order to apply the wound dressing, the user pulls the first gripping tab which lifts the combination urethane film/cover sheet from the release surface of the carrier sheet, thereby exposing the adhesive side of the urethane film. Holding the first tab and, if necessary, the intermediate liner end to prevent the user""s fingers from contacting the urethane film or absorbent pad, the user places this layered sheet combination over the wound. The cover sheet prevents the urethane sheet from stretching while permitting the urethane film to contact and conform to the contours of the patient""s skin. After the combination urethane film/cover sheet has been placed over the wound, the second gripping tab may be peeled away from the other side of the urethane film without stretching or wrinkling thereof. The first and second releasable ends may then be removed, leaving the wound dressing in proper contact with the patient""s skin.
An object of the invention is to provide a method of manufacturing wound coverings incorporating thin urethane films. In a preferred embodiment, the thin urethane films are less than about 1.0 thick and in a more preferred embodiment, about 0.75 mils thick.